Stove and burner assembly

ABSTRACT

A burner assembly for liquid fuels where a body member is rotatable about a central stem member and movable axially thereof to open a fuel valve and also to move a flow control member extending into the nozzle.

This invention relates to stoves, and more particularly relates to stoveand burner assemblies which utilize a liquid fuel such as alcohol.

Existing stoves of this type, which are particularly adapted for use onvehicles and boats, have burners which include apparatus with forged orcast housing requiring a number of machining operations in various typesof machines. These various operations and the transfer between machinessubstantially elevates the costs.

In vehicles such as pleasure boats, mobile homes and trailers, space isalways at a premium, and a stove is generally recessed in a counter,away from the front edge thereof, in order that the stove may be coveredand used as counter space, and also to avoid the creation of unusablespace behind the stove. It is generally a safety requirement that thestove body or pan about the burner be a liquid tight vessel with avolume equal to that of the fuel tank to provide a reservoir for anyliquid that may leak through a non-operating burner.

The burner valves used are generally needle valves with shafts extendingperpendicular to the valve housing and knobs or similar devices attachedto the ends of the shafts for operation of the valves. Where the stoveis recessed, the center lines of the valve shafts are below the countersurfaces and in order to control the valves long extensions of the valveshafts to reach the front surfaces of the counter are required, or thevalve shafts may be equipped with knobs of large diameter so that theyprotrude through slots in the rim of the stove, as shown in U.S. Pat.No. 3,230,947. As described in this patent the shafts extending througha vertical wall in the stove require seals about the openings to preventany leaks. This type of sealing construction is expensive and the sealsmay be inclined to deteriorate with age.

Moreover, presently known burners of the type described have no definiteclosing position marked on the control knobs to show when the burnervalves are properly closed. A needle valve has a tendency to changedimensions every time it is operated in that the closing positionchanges minutely every time the valve is closed.

In view of the aforementioned deficiencies and limitations in liquidfuel stoves, the present invention provides a new stove and burnerassembly in which the burner assembly consists of a minimal number ofparts that can be made with a minimum transfer from one machine toanother; the burner operating controls are accessible from above and donot require any openings in the stove body; and the open and closepositions of the burner are clearly discernible.

Briefly stated, the invention in one form thereof comprises a stove orpan having a burner mounted therein together with a control rod andhandle attached to a body member of the burner and adapted to rotate thebody to control the flow of fuel. Fuel is supplied to a stationarycentral stem member. The body member is rotatable and longitudinallymovable with respect to a burner stem to open a valve to admit fuel to anozzle and also to control the amount of fuel exiting from the nozzle bycontrolling the area thereof.

An object of this invention is to provide a new and improved stove andburner of the type described.

Another object of this invention is to provide a new and improved burnerassembly of the type described.

A further object of this invention is to provide a new and improvedburner control for stoves of the type described.

The features of the invention which are believed to be novel areparticularly pointed out and distinctly claimed in the concludingportion of this specification. The invention, however, both as to itsorganization and operation, together with further objects and advantagesthereof, may best be appreciated by reference to the following detaileddescription taken in conjunction with the drawings, wherein:

FIG. 1 is a top view of a stove embodying the invention;

FIG. 2 is a side elevation, partly in section, of the stove of FIG. 1;

FIG. 3 is a longitudinal half section of the burner of the stove of FIG.1;

FIG. 4 is an enlarged view of a portion of FIG. 3; and

FIG. 5 is a half-sectional view of a portion of another burnerconstruction embodying the invention.

Referring initially to FIGS. 1 and 2, the stove comprises a burner 1basically supported within a frame member 2, which is supported on acutout in counter portions 3 and 4. A cover member 5 is adapted to beplaced over the stove and supported on flanges on frame 2 by extendinglegs (not shown) when the stove is not in use. A dished body or panmember 6 is supported from frame 2.

A fuel reservoir tank 7 supplies a liquid fuel to burner assembly 1through a line 8 coupled to tank 7 at 9 and connected through a coupling10 to burner 1. Burner 1 is supported on a lower portion 11 of pan 6 ashereinafter described. A burner adjustment control member 13 having ayoke-like end is affixed to burner assembly 1 by means of a tighteningdevice such as a bolt 12. Member 13 is movable in an arc, as indicatedin FIG. 1, by means of a handle 14. A low friction material 15, such asa Teflon slide 15 attached to member 13 rides on a surface 16 of pan 6.

The burner assembly 1 includes a pre-heat dish or cup member 17 and ahead 18. The reservoir tank 7 will include a pumping chamber or piston(not shown) to create a head of pressure on the fluid within tank 7. Agrill 19 is supported from pan 6 as by means of upright studs 20, 21 and22. Studs 21 and 22 also provide limit stops for central member 13.

The burner assembly 1 includes a burner body 105 (FIGS. 3 and 4) and aninner stem 106 having a lower portion adapted to receive coupling 10.Body 105 is threadably attached to stem 106 and movable longitudinallywith respect thereto. Stem 106 is supported on pan portion 11 by meansof a lower nut 107 threadably received thereon together with a sealingwasher 108 and a flanged nut 109.

A member 10 having a cylindrical base is received on stem 106 above nut109 and has a threaded portion receiving threaded portion 111 of bodymember 105, to compress sealing members as hereinafter described. Aninternal thread 113 on body 105 engages an external thread 112 on stem106 to permit relative rotation of body 105 on stem 106 and axialmovement of body 105 on stem 106.

The upper portion of stem 106 has defined thereon an invertedfrusto-conical or tapered portion 114 formed complimentary to matingsurfaces 116 of body member 105. Portion 114 terminates in a surface 118from which extends a protruding portion 119 having a needle 120 mountedtherein and extending upwardly therefrom.

Body member 105 includes a nozzle defining member 117 carried by bodymember 105 and threadably received in the upper portion thereof. Thenozzle member 117 includes thereon the tapered or frusto-conical surface115 of body member 105. Body member 105 is formed with internal surfaces121 which receive surfaces 122 of nozzles defining member 117 in sealingengagement.

An annular channel 125 is defined about surface 123 of stem 106 belowportion 124 of member 117. A radially directed passage 126 in stem 106provides communication between passage 125 and a passage 127 leading toa chamber 129a above stem 106. Another passage 128 leads from stem fuelsupply passage 129 to chamber 129a.

The opening 130 (FIG. 3) in nozzle member 117 comprises an uppercylindrical portion 131 and a lower tapered portion 132. Cylindricalsection 130 has an area only slightly larger than the cross-sectionalarea of needle 120.

The cylindrical portion of stem 106 is surrounded by metal washers 135and 136 and a seal 137 as well as sleevelike portion 133 of member 110.This forms a liquid and gas-tight seal between body member 105 and stem106.

In operation, when the burner is to be turned on, lever member 13 isrotated to the desired position. This will move body member 105 andnozzle member 117 upwardly with respect to stem 106 and needle 120.

The mating threads 112 and 113 have a fairly long pitch which willprovide sufficient travel of body member on stem 106 in a little morethan 90°, perhaps 120° of rotation. The travel of needle 120 will befrom a closed position where the needle 120 almost fills the cylindricalpart of the nozzle to a back-off position where the cross-sectional areaof the tapered section 132 less the cross-sectional area of the needle120 is the same as the cylindrical portion 131 of the nozzle. Whilefurther travel may be permitted it would serve no useful purpose.

As the body member 105 is initially moved upwardly with respect to stem106, the fuel under pressure may move through passages 129 and 128 pastthe parted tapered surfaces 115 and 116, allowing the liquid fuel toflow into the nozzle cavity 129a. However, the needle 120 is still inthe cylindrical part of the nozzle opening 130 and the exiting flow offuel is very limited.

Further rotation of burner body lowers the needle with respect to theopening 131 thereby increasing the area between the needle and thenozzle opening. Thus, the tapered surfaces 115 and 116 function only toopen and close a valve defined by passage 128, while the control of flowis accomplished by the relative position of the needle 120 with respectto the end of the tapered part 132 of the nozzle opening.

When the fuel is entering nozzle cavity 129a it will also flow inbetween threads 112 and 113 and fill the thread cavities down to seals135 and 137. Fuel will overflow and be caught in overflow pan 17. Whenthis is ignited it will heat the body 105 resulting in vaporization ofthe fuel for the necessary burning action. While not shown in thedrawings it will be understood that there will be several peripheralrows of openings in burner head 18 to permit flow of combustion air.Passages 126 and 127 permits the fuel in the thread cavities to freelyexpand and vaporize when the burner is preheated. The burner assembly ispreferably formed of brass. When liquid fuel is ignited in pre-heat cup17, body 105 quickly reaches a temperature which will vaporize the fuel.

Besides acting as a flow control, the needle 120 also operates whenmoved to the closed position to remove any combustion residue such ascarbon that may be formed in the nozzle opening.

FIG. 5 shows an alternate embodiment of the invention. In thisembodiment the nozzle defining member 117 consists of an externallythreaded portion threaded to the upper part of the burner body in thesame manner as previously described. However, the interior ofnozzle-defining member 117 is defined with a cylindrical bore 140 andreceives therein an insert 141 which has a tapered surface 142 adaptedto seal against the stem surface 115. Insert 141, while held within bore140, can move axially therein and is backed by a resilient backingmember 143. Backing member 143 is preferably of asbestos. The purpose ofthis construction is to facilitate opening of the burner, since when theburner is operated the burner body 105 and stem 106 assume differenttemperatures, and when the burner has been turned off, body 105contracts more than stem 106 which could tend to lock the burner in aclosed position. With the arrangement shown in FIG. 5, the pressurebetween the tapered surfaces 115 and 116 is relieved by the resiliencyof the member 143.

From the foregoing disclosure it may be seen that the objects of theinvention are efficiently attained. While preferred embodiments of theinvention have been set forth for purposes of disclosure, it is to beunderstood that other embodiments to the invention as well asmodifications to the disclosed embodiment which do not depart from thespirit and scope of the invention may become apparent to those skilledin the art. Accordingly, the appended claims are intended to cover allembodiments and modifications of the invention which do not depart fromthe spirit and scope of the invention.

What is claimed is:
 1. A burner assembly for liquid fuels comprising astem member having an axial fuel passage therein, a body member engagingsaid stem member and axially movable thereon upon relative rotationtherebetween, a valve defined between said stem .[.passage.]..Iadd.member .Iaddend.and said body member, said body member including anozzle having a cylindrical portion and a lower tapered portion, aneedle extending into .Iadd.and substantially filling .Iaddend.saidcylindrical portion of said nozzle .Iadd.to close said nozzle.Iaddend.when .[.the assembly.]. .Iadd.said valve .Iaddend.is in aclosed position and .Iadd.the end of said needle .Iaddend.beingretractable into said tapered portion to control the nozzle opening whensaid body is moved relative to said stem to open said valve.
 2. Theburner of claim 1 wherein said stem and said body member have matingtapered surfaces which define said valve.
 3. The burner of claim 2wherein the tapered surface of said body member is defined on a movableinsert backed by a resilient member.
 4. The burner of claim 2 whereinsaid stem member has the tapered portion on the upper end thereof and afuel passage is defined in said stem through said tapered surface tosaid axial passage.
 5. The burner of claim 1 wherein said nozzle isdefined in a nozzle member threadably received in said body member, andsaid nozzle member also provides the tapered surface of said bodymember.
 6. The burner assembly of claim 1 further including a stove bodyincluding a dished portion, means supporting said burner assembly insaid dished portion and means coupled to said body member and extendingradially therefrom beyond said dished portion for rotating said body. 7.The assembly of claim 6 wherein said extending means is movable in anarc on a flat portion of said stove body.
 8. The burner assembly ofclaim 1 wherein said rotation of said body member substantially 90°about said stem moves said burner between full open and full closedpositions. .Iadd.
 9. The burner of claim 1 wherein the portion of saidneedle extending into said nozzle has a uniform crosssection..Iaddend..Iadd.
 10. The burner of claim 1 wherein thecross-sectional area of the lowered tapered portion of said nozzle lessthe cross-sectional area of said needle is substantially the same as thecross-sectional area of the cylindrical portion of said nozzle..Iaddend.